The invention relates to a system for generating images and spacially resolved spectra of an examination subject with nuclear magnetic resonance wherein electromagnetic coils are provided for the application of fundamental and gradient fields to the examination subject and for the acquisition of the excursion of the atomic nucleii of the examination subject from their position of equilibrium due to a high-frequency magnetic exciting pulse and wherein an image reconstruction means generates an image or, respectively, spacially resolved nuclear magnetic resonance spectra for a predetermined measuring region, such system utilizing a cryostat for containing predominantly superconducting fundamental field coils, said cryostat having a vacuum chamber.
Given known devices of this type, the connection and disconnection of the current in the gradient coils leads to the development of noise which can be bothersome to the patient surrounded by these coils. The reason for the development of this noise is that a force impulse acts on the electrical conductors during connection and disconnection of the gradient current given the presence of the constant magnetic field; such force impulse induces vibration in the carrier tube of the gradient coils present in the known devices. This force impulse producing the vibration is all the greater the shorter the connect/disconnect time of the gradient current, the higher the gradient current and the higher the fundamental field. Demands in this direction are raised, however, for the purpose of producing qualitatively high-grade NMR tomograms.